Whatever kit you decide on try and make the bike take more of the load and not your back by having too much in a camelback
I run a Specialized Henge saddle with a Specialized Swat bandit bolted underneath, this holds a 29er tube, CO2 cannister, tyre levers and pump head
In the Steerer tube i have a Specialized swat tool with integrated chain tool and spare split links
This set up is perfect for local loops where im no more than 5-10 miles from the car should the worst happen
For bigger rides i have a Evoc bag with a shock pump, 2 spare tubes, hand pump which also takes a C02 cylinder, some gaffa tape and a piece of bendable plastic (for sidewall damage repair) couple of zip ties, small roll of bog roll and electrical tape (handy if you get caught short or need a make shift plaster etc…)
Tyres are set up tubeless, i do have a tubeless repair kit but Ive never had to use and now leave it at home